This invention relates to a translucent solid and/or gel prespotting composition for removal of stains and soils from selected areas of fabrics prior to laundering procedure.
Detergent prespotting sticks are known in the art but are subject to a disadvantage of high raw material costs due to high levels of solvent and nonionic surfactant. For example U.S. Pat. Nos. 3,417,023, 3,664,962, 4,289,644, and 4,842,762 claim pretreating compositions containing less than 5 percent by weight of water and the remainder solvent, nonionic surfactant, and gellant. U.S. Pat. No. 4,396,521 teaches compositions containing water levels up to 35% by weight, but requires the use of a substantially water soluble solvent component to form solutions. Compositions containing water soluble solvents are not as effective on oily soils as compositions containing water immiscible solvents. The inclusion of water into the compositions of U.S. Pat. No. 4,396,521 has a dramatic detrimental effect on the removal of oily soils from fabric. The only practical examples taught in U.S. Pat. No. 4,396,521 contain less than 12 percent by weight of water.
Laundry pretreating sticks based on immiscible solvents are taught in U.S. Pat. No. 4,289,644. These compositions are very effective at removing oily soils but suffer from high raw material costs in that they contain less than 10 weight percent of water. This dilemma of cost versus performance has been over come by using novel compositions based on microemulsions.
Microemulsions are mixtures of immiscible liquids that include water, organic solvents, and a surfactant or mixtures of surfactants such that one liquid is dispersed into the other one in very small domains ((1000A). Because they are dispersions, microemulsions have unique physical properties not exhibited by molecular solutions. Specific to this invention is the ability of microemulsions to tolerate significant water levels yet maintain efficacy on oily soils.